Variable speed means for web feeders



E. H. SCHMIDT VARIABLE SPEED MEANS FOR WEB FEEDERS May 29, 1956 3 Sheets-Sheet 1 Filed Feb. 27, 1952 A T TORNE Y.

May 29, 1956 E H, $HM|DT 2,747,866

VARIABLE SPEED MEANS FOR WEB FEEDERS Filed Feb. 27, 1952 3 Sheets-Sheet 2 IN V EN TOR.

ATTORNEY.

y 9, 1956 E. H. SCHMIDT 2,747,866

VARIABLE SPEED MEANS FOR was FEEDERS Filed Feb. 27, 1952 3 Sheets-Sheet 3 IN VEN TOR.

' fi'yarff 50/27/2112? A TTORNEY.

United States Patent VARIABLE SPEED MEANS FUR WEB FEEDERS Edgar H. Schmidt, Wilmington, DelL, assignor to E. I. du Pont de Nemours & Company, Wiimiagten, Del, a corporation of Delaware Application February 27, 1952, Serial No. 273,754 6 Claims. (Cl. 271-2.3)

This invention relates to an improved apparatus for feeding webs, and particularly to an apparatus for feeding a web to other process machinery wherein the speed of through-put is variable.

A Wide variety of web-processing apparatus is designed to operate on an intermittently moving web, a typical process being that wherein it is desired to perforate a web with precision using reciprocatory punch-and-die machinery. Another operation of similar nature is that wherein predetermined lengths of a web are severed by a transverse shearing knife and there are numerous other manufacturing processes in which the instantaneous rate of feed of the web is highly variable, if not actually intermittent. Web materials, such as paper, cellophane, metal foil, textiles and the like, are marketed in the form of large, heavy mill rolls having a high inertia, and the rapid, cyclical tensioning and slackening of the end of the material being operated on subjects the web to very severe stresses. This is disadvantageous for the reasons that the web is often subjected to sudden pulls which either stretch or break it, the whipping action is noisy, and undesirable stresses are imposed on the processing equipmentitself. The apparatus of this invention is adapted to be interposed between the mill roll supplying the web and the processing machinery operating on it, and provides a positive, near-uniform feed in the withdrawal of material. from the mill roll While offering a very low drag resistance to the periodic demand of the processing.

equipment.

An object of this invention is to provide a web feeder which is adapted to withdraw a web from a supply roll at near-uniform speed and feed it to processing apparatus operating at variable speeds without appreciable drag resistance.

Anotherobject of this invention is to provide a web feeder which is adapted to operate over a wide range of processing speeds without the necessity for manual or electrical adjustment.

Another object of this invention is to provide a compact web feeder which is suited to direct mounting on conventional web processing equipment and which requires no alterations for use in conjunction with a wide variety of such apparatus.

The manner in which these and other objects are accomplished will become apparent by reference to the following specification and the accompanying drawings in which:

Fig. 1 is a side elevation of a preferredembodiment of the apparatus, with the face plate of the casing partially broken away, showing the relationship of the apparatus to the mill roll and subsequent processing equipment;

Fig. 2 is a section taken on the line 2--2 of Fig. 1;

Fig. 3 is a section showing the planetary differential mechanism taken on the line 33 of Fig. 1;

Fig. 4 is a detail view of the over-running clutch taken on the line 44 of Fig. 3; and

Fig. 5 is a schematic representation of a second em feeder being denoted by broken line representation.

, The feeder apparatus is a self-contained unit housedi l? which is provided with drilled holes 14 along: the base to permit attachment to the frame members; of the processing apparatus, or to the floor of the manu-- in casing facturing building, whichever is desired.

As shown in Figs. 1 and 2, the web-supporting rolls;

of the feeder are all carried by hearing shafts mounted outboard from the face plate of casing 13, whereby thread-- ing of the web through the apparatus is facilitated. Thecourse of the web leaving mill roll it) is first over idler roll 15, thence between pull rolls 17 and 18, then around dancer roll i9 and, finally, delivery from the feeder to the perforator or other process equipment by passage over idler roll 2! Idler roll 35 is supported on ball bearings carried by stationary shaft as mounted on bracket 16, which is attached to casing 13 by bolts 25, only one of which is shown. The mounting of idler roll 20 is simi ar in all respects, comprising shaft 26, bracket 21 and bolts 27. Upper roll 17 of the pull roll set is an idler roll turned by the friction of the web in contact with its periphery and is supported on bearings 36 spaced by shoulders formed on the interior of 17 and carried by pin 31, to which 37 is attached by nut 32. Pin 31 is secured at the outer end of lever arm 33, journaled on pin 34, which is threaded into the face plate of 13. Lever arm 33 is provided with a recessed boss 35 for the reception of the lower end of compression spring 36, the upper end of which is seated in blind hole 37 drilled in the underside of the upper casing rim, so that roll 17 is continually urged against roll 18 with a force sufficient to overcome any slipping tendencies on the part of the web.

Roll 13 is positively driven by the power output shaft 4i? of the planetary differential mechanism, which is hereinafter described in greater detail, being secured on the projecting portion of the shaft by nut ii engaged with the threaded outer end. Shaft as is ,iournaled in bearing 4-2 disposed within a through passage formed in the face plate of easing l3 and provided with packing &3 (refer to Fig. 3). Spacer ring 4-5 is interposed on shaft 40 between the ring gear or" the planetary and bearing 42, and the end of shaft 35i within the casing is journaled in the bearing indicated generally at 46. Spacer ring 47 on shaft 40 separates bearing 42 from roll 18.

Dancer roll 19 is rotatably mounted on bearings 5%) carried by pin 51, to which 19 is secured by nut 52, in the same manner as hereinbefore described for roll 17. Pin 51 is carried by lever arm 53 keyed to shaft 54, which is journaled in bearings 55 and 56 disposed in the face plate and rear walls, respectively, of casing 113. Shaft 54 is provided with eccentric strap 6%, secured thereto by key 61 and set screw 62, and tapped at its upper end to receive headless screw 63 which is retained in place by lock nut 78. Clevis 64 is supported on screw 63 by nut 65, against Mandrel 12 supporting thecore on which the web is Wound is journaled for freerotation in bearings carried by a conventional supporting. stand (not shown) and the web is pulled from roll 10 by a frictional pull roll set comprising part of the upper-- ratus of this invention, the course of the web through thewhich 64 is biased by compression spring 66 suitably adjusted by nut 67 threaded on the upper end of 63, and is connected with one arm of bell crank 69 by pin 68. Bell crank 69 is secured to rotatable shaft 70, journaled in the face plate and rear wall of casing 13, by set screw 71. Brake shoe 72 is secured to pin 73 journaled in the sides of clevis 74 in the vertically disposed arm of bell crank 69, brake shoe 72 being disposed with its frictional braking surface 75 adjacent the outside periphery of the internal gear of the planetary differential. Spacing screw 76, retained in position by locknut 77, is provided to retain brake shoe 72 in concentric relationship with the internal gear of the planetary.

As will be understood more fully from the description of the operation of this embodiment of the invention, it is desirable to proportion the components of the mechanism translating changes in dancer roll location to compensating changes in speed input so that a reduction ratio of the order of 90 or 100 to l, or greater, is preserved between a given change in dancer roll position and a corresponding change in the position of brake shoe 72. Thus, in one commercial apparatus constructed according to this invention, the center-to-center distance between pin 51 and shaft 54 was 7 /2", the eccentricity of strap was Mr", the distance between centers of pin 68 and shaft was 8% and the distance between centers of shaft 70 and pin 73 was 2 /2", constituting a reduction of 105 to l, which proved entirely satisfactory.

Turning now to the planetary differential mechanism shown in Figs. 3 and 4, sun gear is secured to shaft 40 by key 86, which also extends through the bore of the driven member 87 of an over-running clutch, so that 85 and 87 can be considered integral with shaft 40 for the purposes of operation of the device. Set screw 88 in the hub of sun gear 85 restrains 85 against axial movement with respect to shaft 40 and set screw 89 serves a similar purpose for clutch member 87.

The planet gears90 of the differential, which are preferably three in number spaced equidistantly around sun gear 85, only one being shown in Fig. 3, are carried by short shafts 91. A two-part spider, comprising externally disposed hub 92 and internally disposed hub 93, journals shafts 91 within sleeve bearings 94 carried by each of the hubs, which are secured together as a unitary structure by bolts 95. The spider is supported in freely rotatable relationship on shaft 40 by bearing 96, seated within hub 92, and bearing 97 within hub 93, spacer ring 98 on shaft 40 being provided between shaft bearing 46 and spider bearing 96.

Spur gear 102 is mounted on the step portion of hub 92 in concentric relationship with shaft 40 and is fixedly secured to 92 by bolts 103. The driving member 104 of the over-running clutch is pressed within the bore of hub 93 and therefore rotates with the spider as if it were integral therewith. Internal ring gear 105, in mesh with planet gears 90, constitutes the third component of the planetary and is supported in freely rotatable relationship with respect to the other components by bearings 106 and 107 pressed on to step portions of hub 93; The outside periphery of ring gear is machined smooth over the length designated 108 to provide a surface against which brake shoe 72 is adapted to bear.

As best seen in Fig. 4, the over-running clutch comprising part of the power train is of conventional design, embodying spring-biased rollers 112 which are disposed in notches 113 formed in the periphery of driven member 87. When driving member 104 rotates in a direction urging rollers 112 toward the shallow ends of notches 113, or counter-clockwise as. seen in the drawing, members 104, 112 and 87 are locked together and thus transmit power positively to shaft 40. However, it will be apparent that, if driven member 87 is independently turned in a counterclockwise direction, as by sun gear 85 and key 86, free relative movement is-perrnitted between 87 and driving member-.104, for the; reason that rollers 112 move into the deep ends of notches 113 and rotate freely therein, slipping against the surfaces of both 104 and 87 without transmitting any power therebetween.

The power input to the feeder is through drive sprocket wheel (Fig. 1), which is keyed to shaft 121 of a motor or other power source, not shown, roller chain 122 and driven sprocket wheel 123, casing 13 being provided with aperture 124 for unrestricted passage of chain 122. Sprocket wheel 123 and driving pinion 125 (Fig. 2), in mesh with spur gear 102, are both keyed on countershaft 126 journalcd in the bearing generally designated 127, the outboard end of 126 being threaded for attachment of retaining nut 128.

In operation, it will be understood that the processing equipment, through which the web passes at a variable speed, or intermittently, in the case of an indexing perforator, makes a variable demand on the material stored on mill roll 16, and the web is therefore subjected to a succession of pulls. During the period of time required for a complete cycle of operation of the processing equipment, however, dancer roll 19 moves between definite limits in a vertical plane and therefore frees an increment of web stored during the slack, work-performing interval of the cycle for passage through the equipment during the indexing interval when tension is applied to the web. The normal driving elements of the web feeder of this invention, such as the power source, sprocket wheels, driving pinion and driven spur gear, are chosen so that they will drive roll 18, and indirectly 17, at a constant speed slightly below the mean speed of the web through the processing,

equipment, thereby safeguarding against over supply of the web under any conditions of operation. In one commercial apparatus constructed according to this invention it was found that satisfactory operation was obtained when the web feeder was designed for a normal web supply of approximately 98% of the processing equipments mean demand. The dancer roll-planetary differential combination provides the slight increase in feed necessary to meet the demand of the processing equipment and is restricted in function to always supplying more web.

It will be understood that the main constant speed driving power for the pull roll set 17-18, supplied when brake shoe 72 is out of contact with braking surface 108, is transmitted through roller chain 122, driven, sprocket wheel 123, driving pinion 125, spur gear 102, the spider comprising hubs 92 and 93, which is bolted to gear 102, driving member 104 of the over-running clutch, rollers 112, and the driven member 87 of the over-running clutch, the rotation of shaft 40, keyed to driven member 87, being in a counter-clockwise direction as viewed from the back of the feeder, or as seen in Fig. 4. Under these conditions planet gears 90 will, of course, describe a circular path with the spider, in which they are journaled, and will carry internal ring gear 105 around with them, so that the entire planetary differential mechanism rotates with shaft 40 without transmitting any power to the shaft.

Since the normal speed at which the pull roll set 1718 operates is preselected so that it is slightly below the mean speed of the processing equipment, the extra demand of the latter will be evidenced as an upward pull on dancer roll 19, which, through crank arm 53, eccentric strap 60 and bell crank 69, and appurtenances, urges brake shoe 72 against braking surface 108 on the outside periphery of ring gear 105. This braking retards the counterclockwise movement of ring gear 105 and applies a clockwise driving force to freely rotatable planet gears 90, which thus turn in a clockwise direction. However, since sun gear 85 is keyed to shaft 40, and is therefore not free to move relative to it and thus follow ring gear 105 and planet gears 90, sun gear 85 is turned counter-clockwise, suchmovementbeing permitted by the over-running action of the clutch permitting free movement of 87 with, respectv to 104 in this direction. This driving of sun gear 85 through ring gear 105 and planet gears 90 supplies addi: tional power to shaft 40 and thus to pull roll 18,- which latter thereupon temporarily supplies more web to dancer roll 19, causing it to descend and release brake shoe 72, restoring normal drive to the apparatus until the Webprocessing equipment again demands more work material. From the foregoing, it will be understood that only a relatively small portion of the driving power for the apparatus is supplied through the planetary differential, which may therefore be of small size and light construction. Furthermore, it has been found in practice that heavy, sustained application of brake shoe 72 to ring gear 105 is not required for good results, the brake c011- tact being more in the nature of a light periodical snubbing, which contributes to smooth operation while at the same time reducing frictional wear on these parts. In this connection, the high reduction ratio provided between movement of the dancer roll and corresponding movement of brake shoe 72 is also advantageous, permitting a relatively large movement of dancer roll 19 without abrupt changes in web feed rate which would tend toward over supply.

Where brake shoe 72 is made sufficientlylarge, very low stresses are imposed on the running web by the controlling movement of dancer roll 19, a very practical design being one in which the shoe applies a braking pressure of the order of 115 lbs. or greater for each pound loading on the web. Since the speed compensation effected by the apparatus is entirely by mechanical means, it will be apparent that successful operation is entirely independent of the current speed at which the web is processed, which obviates the need for expensive and cumbersome control auxiliaries, such as electro-optical scanning devices or the like, during start-up, shut-down or any other conditions of operation.

The embodiment of the invention illustrated in Fig. 5 is similar in all respects to that shown in Figs. 1-4, corresponding elements being shown by the same reference characters, except that the arrangement of elements is such that the planetary differential mechanism may be driven at a different speed than the over-running clutch.

This is accomplished by providing a spider 130 in which shafts 91' are journaled, the spider being freely rotatable with respect to shaft 40' on which it is carried by bearing 131. Sprocket wheel 132 keyed on the hub of spider 130 is driven in the same direction as shaft 40 by a separate driving chain, indicated schematically by broken line 133, connected to a power source not shown. The driving member 104' of the over-running clutch is similarly provided with a sprocket wheel 134, secured thereto by key 135, and driving chain 136 connected to a different power source than 133, or to a separate power output member if the same power source is employed to supply both the main and the differential drives.

It will be understood that the operation of the embodiment of Fig. 5 is in all respects similar to that of Figs. 1-4; however, certain advantages can be obtained by separately driving the planetary differential mechanism. Thus, by a proper proportioning of the sizes of planet gears 90' with respect to sun gear 85', internal gear 105 can be made to turn at a very low speed, whereupon an increased mechanical advantage is obtained by application of the brake to surface 108. Or, if it is desired to increase the range of compensating web feed supplied by the planetary, spider 130 may be driven at a greater speed than member 104', whereupon braking of ring gear 105 will produce a greater increase in web feed than is possible where the main and dilferential drives are at the same speed.

From the foregoing, it will be apparent that the web feeder of this invention is simple, versatile and dependable, and that it is subject to relatively wide modification without departing from the essential spirit of the invention, wherefor it is intended to be limited only within the scope of the following claims.

What is claimed is:

1. In a web feeder the combination comprising a pull roll set through which the web is threaded and a dancer roll around which the web is passed, a drive shaft connected to said pull roll set, an over-running clutch mounted on said drive shaft, a constant speed power source oper atively connected with said drive shaft through said overrunning clutch to turn said drive shaft in the direction in which said clutch transmits power and to thereby turn said pull roll set at a preselected web-supplying speed slightly lower than the mean speed of processing equipment served by said web feeder, a planetary differential having a sun gear fixedly attached to said drive shaft, planet gears journaled in a support operatively connected with a constant speed power source and turned in the same direction as said drive shaft and an internal ring gear, and means retarding movement of said ring gear with respect to said sun gear and said planet gears in response to a decrease in the size of the loop maintained by said dancer roll to thereby transmit additional turning power to said drive shaft through said planetary differential in a direction increasing the rate of feed of said web through said pull roll set.

2.. In a web feeder the combination comprising a pull roll set through which the web is threaded and a dancer roll around which the web is passed, a drive shaft connected to said pull roll set, an over-running clutch mounted on said drive shaft, a constant speed power source operatively connected with said drive shaft through said overrunning clutch to turn said drive shaft in the direction in which said clutch transmits power and to thereby turn said pull roll set at a preselected web-supplying speed slightly lower than the mean speed of processing equipment served by said web feeder, a planetary differential having a sun gear fixedly attached to said drive shaft, planet gears journaled in a support operatively connected with said constant speed power source and turned in the same direction and at the same speed as said drive shaft and an internal ring gear, and means retarding movement of said ring gear with respect to said sun gear and said planet gears in response to a decrease in the size of the loop maintained by said dancer roll to thereby transmit additional turning power to said drive shaft through said planetary differential in a direction increasing the rate of feed of said web through said pull roll set.

3. In a web feeder the combination comprising a pull roll set through which the web is threaded and a dancer roll around which the web is passed, a drive shaft connected to said pull roll set, an over-running clutch mounted on said drive shaft with its driven member fixedly secured to said shaft, a constant speed power source, power transmitting means operatively connected to said power source and to said drive shaft through the driving member of said over-running clutch, said power source being chosen to turn said pull roll set at a pre-selected web-supplying speed slightly lower than the mean speed of processing equipment served by said web feeder, a planetary differential having a sun gear fixedly attached to said drive shaft, planet gears journaled in said power ransmitting means and an internal ring gear, and braking means contacting the outside periphery of said internal ring gear in response to a decrease in the size of the loop maintained by said dancer roll to thereby transmit additional turning power to said drive shaft through said planetary differential in a direction increasing the rate of feed of said Web through said pull roll set.

4. In a web feeder the combination comprising a pull roll set through which the web is threaded and a dancer roll around which the web is passed, a drive shaft connected to one of the rolls of said pull roll set, a spider rotatably carried by said drive shaft, an over-running clutch interposed between said spider and said drive shaft with the driving member of said clutch secured to said spider and the driven member secured to said drive shaft, a planetary differential having a sun gear secured to said drive shaft, planet gears journaled in said spider and an internal ring gear, a constant speed power source operati'vely connected to said spider turning said spider in a direction transmitting power through said over-running clutch and at a pre-selected speed slightly lower than the mean speed of processing equipment served by said web feeder, and braking means contacting the outside periphery of said internal ring gear in response to a decrease in the size of the loop maintained by said dancer roll to thereby transmit additional turning power to said drive shaft through said planetary difierential in a direction increasing the rate of feed of said web through said pull roll set.

5. In a web feeder the combination comprising a pull roll set through which the web is threaded, a dancer roll around which the web is passed carried by a lever arm journaled to oscillate in a vertical plane, a drive shaft connected to one of the rolls of said pull roll set, a spider rotatably' carried by said drive shaft, an over-running clutch interposed between said spider and said drive shaft with the driving member of said clutch secured to said spider and the driven member secured to said drive shaft, a planetary differential having a sun gear secured to said dri e shaft, planet gears journaled in said spider and an internal ring gear, a constant speed power source operatively connected to said spider turning said spider in a direction transmitting power through said over-running clutch and at a preselected speed slightly lower than the mean speed of processing equipment served by said web feeder, a bell crank journaled to oscillate in a plane parallel to the planetary, a brake shoe carried by one arm of said bell crank in a position to bear against the external periphery of said ring gear, an eccentric strap journaled to oscillate in accompaniment with said lever arm, and a link connecting the other arm of said bell crank with said eccentric strap.

6. The improvement of claim 5 wherein said lever arm, eccentric strap, link and bell crank are proportioned to maintain a reduction ratio greater than about 90 to 1 between vertical displacement of said dancer roll and corresponding movement of said brake shoe.

References Cited in the file of this patent UNITED STATES PATENTS 1,437,734 Kessler Dec. 5, 1922 1,918,984 Richardson July 18, 1933 2,171,610 Szekely Sept. 5, 1939 2,209,692 Fulk July 30, 1940 2,331,684 Henningsen Oct. 12, 1943 2,364,309 North Dec. 5, 1944 2,402,547 Giliillan June 25, 1.946 2,444,448 Kannenberg July 6, 1948' 2,475,691 Bonebrake July 12, 1949 FOREIGN PATENTS 352,810 Italy Sept. 23, 1937 

1. IN A WEB FEEDER THE COMBINATION COMPRISING A PULL ROLL SET THROUGH WHICH THE WEB IS THREADED AND A DANCER ROLL AROUND WHICH THE WEB IS PASSED, A DRIVE SHAFT CONNECTED TO SAID PULL ROLL SET, AN OVER-RUNNING CLUTCH MOUNTED ON SAID DRIVE SHAFT, A CONSTANT SPEED POWER SOURCE OPERATIVELY CONNECTED WITH SAID DRIVE SHAFT THROUGH SAID OVERRUNNING CLUTCH TO TURN SAID DRIVE SHAFT IN THE DIRECTION IN WHICH SAID CLUTCH TRANSMITS POWER AND TO THEREBY TURN SAID PULL ROLL SET AT A PRESELECTED WEB-SUPPLYING SPEED SLIGHTLY LOWER THAN THE MEAN SPEED OF PROCESSING EQUIPMENT SERVED BY SAID WEB FEEDER, A PLANETARY DIFFERENTIAL HAVING A SUN GEAR FIXEDLY ATTACHED TO SAID DRIVE SHAFT, PLANET GEARS JOURNALED IN A SUPPORT OPERATIVELY CONNECTED WITH A CONSTANT SPEED POWER SOURCE AND TURNED IN THE SAME DIRECTION AS SAID DRIVE SHAFT AND ON INTERNAL RING GEAR, AND MEANS RETARDING MOVEMENT OF SAID RING GEAR WITH RESPECT TO SAID SUN GEAR AND SAID PLANET GEARS IN RESPONSE TO A DECREASE IN THE SIZE OF THE LOOP MAINTAINED BY SAID DANCER ROLL TO THEREBY TRANSMIT ADDITIONAL TURNING POWER TO SAID DRIVE SHAFT THROUGH SAID PLANETARY DIFFERENTIAL IN A DIRECTION INCREASING THE RATE OF FEED OF SAID WEB THROUGH SAID PULL ROLL SET. 